MEs such as mobile telephones include a UICC which, among other things, holds secure data for identifying the user to the core network. The UICC is a smart card that has an inbuilt microprocessor and memory which can run a number of software applications. The UICC is powered by the battery within the ME. The standards setting Organisation ETSI is in the process of finalising Release 7 of its standards documents (including TS 102 221, TS 102 600 and TS 102 223) relating to the interaction between the ME and its UICC. This standards documentation specifies that the ME negotiates the maximum power supply that will be made available to the UICC before any applications are selected/activated when the ME is powered up.
This current power negotiation mechanism (over the USB interface) is based on the following request and response:                a) Request Sent by the ME to the UICC (Get Interface Power Request)        
OffsetFieldSizeValueDescription0bmRequest1‘C0’/‘C0’ for Get Interface Power‘40’‘40’ for Set Interface PowerCharacteristics of request:b8:1 = Device-to-host/0 =Host-to-deviceb7 . . . 6: Type2 = Vendorb5 . . . 1: Recipient0 = Device1bRequest1‘01’/Get Interface Power Request‘02’Set Interface Power Request2wValue2‘0000’4wIndex2‘0000’6wLength2‘0002’Number of bytes in thedata stage                b) Response Data Sent by the UICC to the ME:        
OffsetFieldSizeValueDescription0bVoltageClass1Indicates the voltage classes supported by the UICC.If a class is supported, the corresponding bit is set to 1.b1Class A, reserved for USB 2.0 (optional use,not specified by ETSI SCP)b2Class Bb3Class C′b7 . . . 4Reserved for Future Use, shall be set to 0b8Class B activation preferred (see clause 7.1)1bMaxCurrent1Maximum current that the UICC requires for bestperformance, expressed in 2 mA units.e.g. ‘0A’ indicates 20 mA.